High refractive index acrylic materials are known for use in intraocular lenses (IOLs). For example, U.S. Pat. No. 5,290,892 discloses high refractive index acrylic materials suitable for use as IOL materials. The materials are foldable and thus capable of being inserted through small incisions. These acrylic materials contain, as principal components, two aryl acrylic monomers.
In some cases, foldable acrylic intraocular lenses develop “glistenings” or “vacuoles” when implanted in humans or soaked in water at physiological temperatures. These microvacuoles appear to be pockets of water approximately 1 μm or greater in diameter. Glistenings are often too small to be seen by the naked eye, but are sometimes observed using a slit-lamp. Although glistenings have no detrimental effect on the function or performance of IOLs made from acrylic materials, it is nevertheless cosmetically desirable to minimize or eliminate them.
Published U.S. Patent Application 2006/0275342 A1 discloses ophthalmic device materials, including IOL materials, containing less than 15% by weight of certain polymerizable surfactants. The polymerizable surfactants are poloxamers and poloxamines, which are generally available under the PLURONIC and TETRONIC tradenames. One advantage of adding such polymerizable surfactants as comonomers in forming polymeric devices is said to be changed or improved device surface properties, such as lipid or protein uptake. It was determined that the functionalized surfactants did not affect mechanical properties of the device materials as the addition of the polymerizable surfactants produced no real change in the modulus or tear strength (see Example 17 of 2006/0275342 A1). The surfactants are chemically modified to make them polymerizable as comonomers. When unmodified surfactants were incorporated into a hydrogel contact lens material during polymerization, it was noted that upon hydration the lenses would become cloudy. When methacrylated counterparts of the unmodified surfactants were used, however, optical clarity was maintained after hydration (see Example 16 and FIGS. 6-8 of 2006/0275342 A1).